Chapter the Fourth
Things Heat Up
"Let's just keep our feet firmly on this world," Brother Matthew said to his enthusiastic colleague, who's flight of extraterrestrial fancy had the potential for taking their discussion beyond acceptable limits. Space travel indeed, what next? He picked up a stick of kindling wood that they had been using in the stove to heat the water.
"You mean," he said, turning the stick of wood over and over in his hands, "that within this stick is a fixed amount of potential energy?"
"That is what the law says," answered Brother Joseph.
"So when we burn this stick, the energy it contains is released as heat, a fixed amount of heat?"
"It may be a bit more complicated than that, but the rough answer is - yes."
"So," said Klacel moving to the stove and the litter of pans on its surface, "in this stove we move the heat from the stick of wood and into the water in these pans, and the water gets hot."
"Agreed."
"But there is something not right here," Klacel mused, tapping the stick of wood on the stove, then picking up the smallest pan, "if I move the heat from this stick into this amount of water the temperature in the pan will probably go to nearly boiling. But," and here he picked up the largest pan on the stove, "if I move the heat from the same stick into his amount of water, the temperature will only go up a few degrees. That does not seem right. Why are the two temperatures different, we used the same amount of energy?"
"You are confusing 
- 'heat' with 'temperature'," Brother Gregory told him, "the two things are not the same. If you put your hand on that small pan of water after it has been heated to near the boiling point, it will probably scald you. A small amount of water at 95 degrees Centigrade is much hotter than that giant pan of water heated to only 30 degrees Centigrade. But, the total amount of heat in the giant pan of water is much greater than that in the hotter, but smaller pan of water."
Klacel still looked confused, so Brother Joseph tried to help.
"Temperature is only a measure of the degree of 'hotness' or 'coldness', not necessarily the amount of - heat it contains," he said, "In the example you were using, if we were to take the two pans of water, one small and one large, put a - thermometer into both and then burn sticks of wood under them until they both reached 50 degrees Centigrade, what would we see? Both quantities of water would have reached the same temperature, but we might have had to burn one stick of wood to make the small pan reach that temperature, while it might have taken ten or twenty sticks of wood to make the larger pan reach exactly the same temperature. The larger pan, therefore now has more heat in it than the smaller pan by at least a factor of ten, even though the temperatures are the same."
In a distant part of the monastery Prior Sembera was busily, and vainly, ringing the Vespers bell, but down in the laboratory three of his monks did not hear him at all.
Klacel strode back to the table carrying his stick of wood and a small pan of water. "Write this down," he said to Mendel, who had taken on the role of scribe for their scientific adventures. "we need a standard unit of heat, here is what I suggest, put a thermometer in this pan of water and note its temperature. Then burn sticks of wood until that temperature goes up ten degrees. Count how much wood we have burned, and that amount will then become our standard."
"That's a good idea," said Mendel, writing away, "but I think it has already been done in England. The English have a unit of heat they call the 'British thermal unit', which they claim is the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. Herr Joule and others use it a lot in their calculations."
"Then we need our own unit, something Czech," Klacel insisted, "we could call it the horko." which even Brother Gregory knew was the Czech word for 'heat'. "We could use the newer French metric system of units, and add our unit of heat to that set of standards."
"What would you suggest?" Mendel asked, trying to humor his enthusiastic friend.
"Hummm, yes, let me think," Klacel pondered, tapping the stick of wood on his chin until a sharp edge stabbed him slightly. "Ouch! What about ... 'The amount of heat needed to raise the temperature of one liter of water by 100 degrees Celsius' ... that would work!"
"It would," said Brother Gregory with a grin, "so let's at least use it in our discussions. But there is one problem, your new Horko heat measuring unit is a very large one. It would only take one Horko to raise the temperature of that entire pan of water from freezing to boiling, I think - a more practical unit would be ... 'The amount of heat needed to raise the temperature of one liter of water by one degree Celsius' ... then at least it would take 100 units to bring a liter of water to the boil."
"Very well," Brother Matthew conceded, "then let us call your unit a Maly Horko, which means 'small heat', how about that?"
"How about some sleep," said Brother Joseph forcefully and not too successfully hiding a yawn. He was exhausted by his day of scientific preparation and his evening of scientific discussion. "Tomorrow we should be able to see if any of our wine-rods are growing on the solid broth, and we will then have to decide what to do next. Let's get to bed and start tomorrow with fresh minds and fresh ideas."